For the study, researchers identified the genotypes of 46 people (23 couples) as either GG, AG or AA. People who had a GG genotype were more "pro-social," while people with an AG or AA genotype were less likely to be empathetic or have parental sensitivity, and also had fewer positive emotions. (MSNBC reports that there are about 3 billion different letters that make up our genetic code.)

Then, researchers videotaped the couples and had each partner describe a moment of suffering. Outside observers then viewed these videotapes, and were asked to rate how caring, trustworthy and kind a person was as he or she listened to his or her partner telling the story of suffering.

Researchers found that of the 10 individuals rated the most "prosocial," six of them had GG genotypes. And of the 10 individuals rated "least trusted," nine of them had an AA or AG genotype. MSNBC reports that the outside observers were able to detect these genotypes in just 20 seconds.

"It was amazing to see how the data aligned so strongly by genotype," study researcher Sarina Rodrigues Saturn, an assistant professor psychology at Oregon State University, said in a statement. "It makes sense that a gene crucial for social processing would yield these findings; other studies have shown that people are good at judging people at a distance and first impressions really make an impact."

The reason why the gene seems to make such a difference in how caring a person is perceived, is because it is associated with the body's oxytocin receptor. Oxytocin, a hormone, is known to be linked with trust, love and social recognition.

"The oxytocin receptor gene in particular has become of great interest because a select number of studies suggest that it is related to how prosocial people view themselves," study researcher Aleksandr Kogan, a postdoctoral fellow at the University of Toronto, said in the statement. "Our study asked the question of whether these differences manifest themselves in behaviors that are quickly detectable by strangers, and it turns out they did."

However, that's not to say that people who don't have the GG genotype are doomed to be unfriendly people forever. There are other factors that can affect how friendly or kind a person is, and "oxytocin receptor gene is one of those factors," Kogan said.

Other research shows that being caring is good for health. University of California researchers recently released a study showing that being able to help a loved one is linked with activation of a brain region associated with reward, the Daily Mail reported.

In that study, published in the journal Psychosomatic Medicine, researchers gave electrical shocks to 10 men as their girlfriends looked on, according to the Daily Mail. MRIs revealed that the women who were able to hold on to their boyfriends' arms had more activation in the ventral striatum and septal areas of the brain, compared with women who weren't able to support their boyfriends.

For more benefits of caring and kindness, read author and HuffPost blogger David R. Hamilton's post here.